Briefing Package for W3CTM Math Activity

1. Executive Summary

This document sets the stage for the continuation of
development and support for the World Wide Web Consortium
(W3C)
Mathematical Markup Language (MathML) 1.0 Specification. MathML 1.0
provides a solid foundation for representing mathematical
expressions. However, a number of critical requirements
dating back to the original HTML-Math Working Group Charter
remain to be accomplished, and other goals developed as a
result of MathML implementations or of feedback from the
community remain to be met. With MathML 1.0 in hand, we are
offered a unique opportunity to ensure effective math on the
Web through its widespread acceptance, and it seems very
desirable to maintain the present MathML 1.0 Recommendation,
and to further develop the specification. The current Math
Working Group proposes that the W3C establish a new Math
Working Group to continue the work of the W3C Math activity.
The proposed revision MathML aims to reduce the overhead
involved in publishing scientific and technical Web content,
while increasing its scope to accommodate new areas of
science. We expect that as a result of a new MathML the suite
of tools for authoring, managing, transforming and rendering
MathML will continue to evolve and leverage the relationship
between MathML and other W3C specifications.

2. Current W3C Status

2.1 Existing work

W3C has an existing Math Working Group which
by charter
shall finish its work in June 1998. The
MathML 1.0 Specification
is a product of the W3C's Math Working Group and was issued
as a W3C Recommendation on the 7th of April 1998. MathML is
an XML application for representing
mathematical expressions, their presentation, their
semantics, or both. MathML consists of approximately 100
elements and their attributes, which can be divided into two
major categories: presentation elements and content
elements. Presentation elements may be used to express the
two-dimensional layout of mathematical expressions. Content
elements are used to express the semantics of mathematical
expressions up to the level of calculus. Content elements
have a default presentation but may be combined with
presentation elements to customize the layout of
expressions.
(
Some MathML examples.)

The proposed new working group is positioned as a
continuation of the present Math Working Group and would be
chartered within the W3C
User Interface Domain.

2.2 Architectural Constraints

The relationship between MathML and other W3C
technologies is crucial. The Math Working Group has made
available a separate
requirements document
that describes the demands that MathML makes on browsers,
eXtensible markup Language(XML), the Document Object Model (DOM),
style mechanisms --- eXtensible Style Language
(XSL), Cascading Style Sheets (CSS), etc. ---,
and rendering. The requirements that MathML makes of these
mechanisms, and of browsers generally, are not unique to
MathML and are useful in other W3C contexts. If necessary
this document will be updated as the group progresses.

3. Proposal: Mathematical Markup Language Working
Group

3.1 Introduction

Efforts to define a specification for mathematics in HTML
have been underway in the W3C for several years. Dave
Raggett made a proposal for math in HTML in 1994. Although
that proposal was not ultimately incorporated into HTML 3.2,
a panel discussion at the WWW IV Conference in April 1995,
and representation by W3C members, demonstrated that there
was clear interest in pursuing a specification for
mathematics on the Web. A group was formed to discuss the
problem further.

In the intervening years, the W3C and the math working
group have both evolved substantially. The small informal
math group has grown, and has been formally reconstituted as
the W3C HTML-Math Working Group, later shortened to the W3C
Math Working Group. The current Working Group is composed
of experts from commercial publishers and software vendors,
as well as not-for-profit publishers and research
organizations from both Europe and North
America.

The W3C Math Working Group's main achievement thus far
has been the production of the MathMLTM 1.0 specification.
MathML is well-suited to markup emphasizing the
presentational quality, as well as the semantic aspect of
math formalism. It can serve as markup for high-quality math
composition. MathML has been outfitted with enough special
XML elements to carry much of the meaning of mathmath up to
roughly the beginning of college level. Furthermore, since
it is an XML application, it offers itself naturally to the
commercial publishing realm which wishes to use the same
source for electronic browsable copy, as well as for
high-quality rendering through traditional print.

The MathML 1.0 specification is a powerful low-level
language primarily aimed at facilitating the building of tools
for communicating math over the Web. As a consequence, it
is rather complex, and experience has shown
that end users expecting complete solutions for authoring
and publishing scientific documents on the Web are easily
overwhelmed. To reach its full potential as a framework for
sharing mathematical information over the Web, further
support for MathML both in software and in other
Web standards is required. This in turn requires active
maintenance and development of the MathML specification
itself.

We propose that the World Wide Web Consortium establish a
Math Working Group as described in this briefing package. The
Math Working Group should be directed to make further
progress following the work of the W3C Math Working Group
which shall have finished its charter in summer 1998. The
Math Working Group should work through the remaining open
issues identified by that Math Working Group as still of
importance. In particular, the Math Working Group shall be
responsible for the maintenance and updating of the MathML
1.0 Specification adopted as a recommendation by the W3C
following upon the efforts of the foregoing Math Working
Group, and shall continue the push towards making the work
of science and mathematics more readily communicable and
accessible through the WWW.

3.2 Scope of the Activity

This briefing package is being issued because of strong
member interest. We divide the scope of the Math Working
Group activity into three sections.

3.2.1 General support

To work toward the
effective spread and adoption of MathML it is desirable to
have a center where those who are using it can turn for
advice on some of the perhaps subtle points of the
specification. In addition, to promote MathML's use a suite
of typical examples of MathML in action has to be devised
and the standard has to be maintained. There will be errors
to be corrected and extensions to be made.

More generally, an outline of implementation strategies
needs to be prepared.

MathML is not intended as a direct authoring language.
The Math Working Group decided not to endorse a single input
syntax since it determined there could not be one that would
suit all. Instead, the Math Working Group decided that it
should encourage interested parties to develop tools for
authoring, generating, translating, or exporting MathML.
However, it is important to the success of MathML that input
syntaxes purporting to feed into MathML actually do so
reasonably. If not the usefulness of MathML as a language
will be degraded. We will offer support to organisations
working on input syntaxes.

3.2.2 Presentation

In order to realize the full
potential of the presentation markup of MathML, it is
necessary that the placement of inclusions within an HTML or
XML document be subject to better control. This is also
needed by other formatting driven applications. The
Document Object Model, which is undergoing refinement by the
DOM WG, should be monitored to ensure that it is understood
how to use it to realize MathML rendering in Web browsers.

The promise of style sheets, and in particular of CSS and
XSL, is that they might be used to provide a
platform-independent rendering mechanism for MathML. The
Math Working will work with the XSL Working Group toward
inclusion of such things as sufficient math flow objects to
render MathML and other scientific formulas.

A very new development has been the submission of Notes
to the W3C concerning two-dimensional vector graphics
languages. The probable chartering of a Scalable Vector
Graphics (SVG) Working Group within the Graphics Activity
of the User Interface Domain of
the W3C is welcomed by the present Math Working Group.
The PGML and VML Notes submitted to the W3C, seem
to advocate a graphics language rich enough to support
the finest nuances of MathML rendering. If such an SVG
Working Group is formed then it would be a task of the Math
Working Group to serve as a liaison between implementors of the
MathML Specification as they may be affected by the
developing SVG specification.

3.2.3 Content

Though the content tagging already in MathML 1.0 does
support most of math up to early college level, there are
simple extensions that have already been suggested. How to
make such extensions, and which to choose to endorse as
recommended requires a body to oversee the process
reliably.

In addition, a large-scale effort which is oriented
toward the semantic encoding of math is OpenMath, with which
the Math Working Group already has collaborated.
OpenMath has so far adopted some of the work that was done
by the Math Working Group. It may be expected that
some of the content tagging of MathML should be adjusted in
the light of the experience gained on the semantic front
through OpenMath work.

The mathematical properties of content elements are
largely conveyed through default attributes values. The
management of these attributes exactly parallels the
management of attributes of flow objects as found in CSS2
and the current work on XSL. Mechanisms such as macros or
style sheets for managing these default attributes need to
be investigated.

3.3 Market for the activity

The target market
segment remains the same as the original working group with
several additions due to recent W3C activities. Indeed, the
potential audience for a mathematics specification for the
Web is quite large, encompassing students and teachers at
nearly all educational levels, professional researchers from
many different scientific disciplines, software vendors,
scientific publishers, etc.

Publishers have an immediate need for displaying
mathematical content on the Web. Publishers have legacy
data in TeX and/or SGML and presently have very limited
options for displaying such documents on the Web. The Math
Working Group should encourage the development of converters
of legacy data. There is presently work afoot here.

Software vendors who wish to link their products for
manipulating mathematical expressions with mathematics in
Web pages are served by MathML. This might be accomplished
by cutting and pasting a mathematical expression from a Web
page into the mathematical software, or by other more direct
means.

With the emergence of the DOM, web component
developers will be able to control the actions of MathML
rendering applications. A new market for scientific web
components that interact with MathML renderers is beginning to
emerge.

3.4 Structure of Activity

A new working group will be formed, charged to continue
to work of the current W3C Math Working Group, in the
User Interface domain. The proposed charter includes the list of
deliverables, the start and end dates and the level of
commitment required to participate in the work.

Involvement with other W3C activities and working groups
will be an important part of the MathML continuation effort.
This involvement will be accomplished by cross membership
and interest group involvement as well as making use of the
W3C Hypertext
Coordination Group. The MathML Working Group
charter and
requirements document detail the expected relationships
with other working groups.

3.5 Resource Statement

3.5.1 W3C Resource Commitment

The proposed W3C Math WG requires a minimum of resources
from the Consortium, as is the case with the current Math
working Group. In particular, the proposed group
requires

A W3C staff contact to serve as liaison to the W3C
team. As is currently the case, this staff contact need
only devote a small fraction of his or her time to
monitoring the MathML activity.

Access to a W3C teleconference bridge every other week.

Logistic support for planning face to face meetings
twice a year.

An archived mailing list for WG use, and a public archived
mailing list.

Space on the W3C web site.

3.5.2 Member Resource Commitment

Working Group members will need to make a commitment of
preferably 20% of their time, for one year, to qualify as a
fully participating member. As the Math Working Group sees
fit it may accept participants with special expertise who
can contribute no less than 10% of their time.

It is expected that the members of the W3C who have
contributed personnel resources to the successful work of
the present W3C math WG will wish to continue their
involvement with math on the Web. The vote approving MathML
as a Recommendation suggested a wider interest in using
MathML than just those directly involved in the Working
Group writing it, as, of course, it should be. Therefore we
may expect new involvement.

W3C Members may also undertake to review one or more
working documents without fully participating in the Working
Group activity. There is no participation requirement for
this, apart from timely delivery of review comments for the
draft in question.

The proposed Working Group schedule is for 18 months. At
a minimum contribution of 20% of a full time equivalent per
principal member, with 10 such members the overall resources
contributed to this working group would thus be 3
person-years.

Participation requirements by W3C members, by the W3C
team and by invited experts are described in the
charter.

3.6 Projected Schedule

The Working Group, if approved, will commence work at the
beginning of September 1998 by establishing a mailing list
and by then holding the first of its face-to-face meetings
in October 1998.

The Working Group will hold bi-weekly teleconferences as
described in the charter, and will work to
the following schedule:

First public requirements document: May 1998 (by
previous Math Working Group)

New Math Working Group meeting: October 1998

Working Group meeting: April 1999

First Working Draft of MathML revision: May 1999

Working Group meeting: August 1999

Second Working Draft of MathML revision: October 1999

Working Group meeting: November 1999

Proposed Recommendation for revised MathML: Jan 2000

Working Group termination: February 2000

The Working Group will terminate in February 2000, after
comments arising from the revised MathML Proposed Recommendation
ballot have been incorporated.

4.2 Participant Lists

The following organizations, most already members of the
W3C, have expressed their interest in MathML through their
involvement in the current Math Working Group. We expect their
support for the proposed new activity:

The chairs of the new Working Group will be Patrick Ion
<ion@ams.org>
(American Mathematical Society / Mathematical Reviews) and
Angel Diaz <aldiaz@us.ibm.com>
(IBM Research Division).

4.3 Acknowledgments

This briefing package follows the guidelines specified in
the
World Wide Web Consortium Process
document. Portions of this document are based on the recent
Mathematical Markup Language (MathML) 1.0 Specification,
MathML Executive Summary, and Math Working Group W3C
requirements statement, as well as on other W3C briefing
packages.